modular synthesis
[To find out the basics of synthesis with audio examples, click here, or to hear music and emulations of real world sounds that were created using modular synthesis, or to download Nord Modular G2 patches, click here.]

Modular synthesis is a method of synthesis involving the building or 'patching' of various modular components such as oscillators, filters and envelopes in an open architecture environment. It is without doubt, the most versatile form of synthesis available and able to recreate most sounds (including 'real world' sounds) extremely convincingly. To hear .mp3 audio examples of finished patches, click here.

Apart from having a far wider variety of modules available than on a conventional synthesiser, modular synthesis also allows the patching of almost any input to any output and vice versa. This affords great freedom, not just to decide which order of modules the signal path will follow, but also to do things like using audio signals as modulation sources, and modulating modulation sources. There are too many varieties of modules to mention all of them here, but the main groups are briefly explained below.

module groups

A module in modular synthesis can be described as a self-contained part, or component, of a modular system. Different modules will have different inputs and outputs and the patching, or connecting, of these with other modules' inputs and outputs forms the basis of building a complete modular system.

Although modular synthesis uses some of the same basic modules of synthesis, such as oscillators, filters and envelopes, there are far more variations of each available and often featuring more control possibilities, ie. modulation inputs on envelope parameters, etc. Being able to modulate virtually every aspect of a sound is essential for recreating real world sounds accurately and very useful for attaining desired musical sounds also. Below are details of the kinds of modules not usually found in conventional synthesisers.To find out about the modules used in conventional synthesisers, click here.

module groups  •  step sequencers

These modules usually have eight or sixteen steps, with various outputs on each and allow patterns of notes or levels to be created. They can be used as user defined arpeggiators, as modulation sources, or be linked together to create longer sequences, or even whole songs. The number of steps in a sequence, the direction of play and the starting step number can usually all be modulated to create complex and/or semi-random sequences. An LFO is used as a 'clock' input to ensure accurate timing.

module groups  •  slew/glide

Some synthesisers have a basic version of this module permanently assigned to pitch, called portamento which creates a pitch ramp between the last note played and the next. What it actually does, is smooth abrupt changes in control signals and it can even be patched to alter LFO shapes, or used as a crude low pass filter.

module groups  •  sample and hold

When these modules receive a trigger pulse, they take a reading of a modulation source at their input and hold that value at their output until the next trigger pulse arrives. This is good for having a sound that changes on each key press, without the continuing sweep of the modulation source being heard while the key is held, or any operation where a value is required to be temporarily remembered. These modules can be considered as switch modules.

module groups  •  switches

This useful group have several inputs and/or outputs and enable the user to switch between these signals, either manually or automatically, triggered a modulation source. This allows for applications such as wave sequencing, where several different sounding oscillators are connected to a switch and the value of an LFO's output signal controls which oscillator is heard, or simply to allow a user to choose between different sonic possibilities in a patch.

module groups  •  random

This group of modules either continuously, or on demand, generate and output random values, which are essential for any patches recreating sounds from nature, such as the ones available for auditioning or downloading on the nord modular g2 patches page... click here to go there. They work well as modulation sources and are also widely used in experimental, self generating music patches, such as the attached Metamorphosis performance... click here to go there. In these types of patches, the random modules are used in conjunction with note quantising modules which shift the random value to the nearest pre-defined note value.

module groups  •  level

These modules all affect the level of both control and audio signals. Some add, some multiply, some amplify, while others can change the amplitude envelope of a sound, or produce amplitude modulation. There are also several ways of inverting and/or converting signals from positive to negative or bi-polar (both positive and negative) or any combination of these processes. Noise gates, which can be used for rhythmic modulation effects, are also in this group... click here to find out how to create rhythmic effects with a noise gate.

module groups  •  logic

Logic modules use logic signals to trigger other modules, such as sample and hold or step sequencer modules and to perform certain actions at certain times, such as taking and holding a value reading, or restarting a sequence. Logic signals only have two states; high = max level and low = zero level. Logic inputs respond to any signals that cross from positive to negative or vice versa (ie. pass the zero crossing point) and so can also respond to modulation and audio sources with interesting effects.

Logic pulse modules use pulse waveforms to adjust the length of the incoming gate signal, ie. the note length. Connecting a modulation source, such as a sequencer, to the gate length input will allow notes of differing lengths to be played as the sequencer progresses through each step. This is one way that more complex sequences can be created.

There are also modules that can delay, divide or modify logic signals, to synchronise events. Logic gates are commonly found in digital circuits and can perform simple logic tasks, depending on whether signals are present on their two inputs, ie. an 'AND' gate will only output a signal if signals are present on both its input one AND input two, whereas an 'OR' gate will output a signal if signals are present on either its input one OR its input two.


other modules

Other modules available in modular synthesis include basic samplers and a wide variety of effects, sound shaping and distortion modules. There are also note quantising and key scaling modules, that are commonly used with random generating modules for creating randomly generated music - the attached Metamorphosis patch is an example of this... click here to download or hear it. There are a variety of MIDI modules available that allow interaction between the modular synthesiser and a sequencer, or any other piece of MIDI equipment. The last other common module types are audio input and output modules and a wide selection of mixer modules, either for logic, control, or audio signals.


analogue or digital?

Unless you are rich, or already have a decent number of analogue synthesis modules, the answer to this question is simple. With digital modular synthesis, a whole system can cost less than one or two analogue modules. There is of course the old argument that digital equipment does not sound as good as analogue and there may be a shred of truth in this, but that is not to say that unbelievable and amazing sounds can't be produced from digital systems. Far from it.

It would be unfair to talk about modular synthesis without giving at least a mention to Analogue Systems, one of the leading analogue modular synthesiser module manufacturers... click here to go to their website. Back in the digital domain, there are two main contenders and they are the Clavia Nord Modular G2 digital synthesiser system and Native Instruments Reaktor 5. The main differences between them are noted below.

digital modular synthesis  •  Clavia nord modular g2

Starting from around £500 (UK) for a G2 engine, which is a 19" rack mountable G2, without the control panel or keyboard, controlled instead by a computer via USB, this is the more expensive option. The main benefit to this system is the DSP in the machine that powers the sound creation. This DSP amount can be doubled for around an extra £250 (UK) by buying an expansion card. Unlike Reaktor, the G2 uses no computer CPU cycles while being used, except for a tiny amount when using the editing software. Also, the editor is simple to use, while still offering a great deal of control with over one hundred and sixty different modules. There are four slots in a G2, with each being able to hold a separate patch and communicate with the other slots via internal busses or MIDI. One downside to the G2 is that there are no sampler modules.

There are also keyboard versions of the G2, that have a multitude of controls and multi screen displays for parameter feedback. To find out more about the Modular G2 series from the Clavia website, click here. If you are interested, you can download the free editor software that will run on both Windows and Mac OSX computers from the Clavia website. Click here to go to the relevant download page. If you have a G2, you can find many more free patches and performances from the forum index page of the electro-music website... click here to go there.

digital modular synthesis  •  native instruments reaktor

Reaktor 5 is a computer software application and at somewhere in the region of £250 (UK), it can be purchased for approximately half the cost of a G2. It runs on both Windows XP and Mac OSX host computers and comes with dozens of high quality, pre-designed software instruments including samplers, drum machines and effects that have been created using the provided modules. As well as a large selection of these pre-designed 'building blocks', Reactor also provides the ability to modify the individual electrical components within each module, or even create your own from scratch if you have the know how.

There is no doubt that Reaktor offers more than the G2, but one downside is that it uses a significant portion of available cpu cycles of reasonably up to date computers (using more cycles for bigger patches) and if you are running a sequencer program as well, your computer could struggle. The other problem with Reaktor is that as it offers so much, it is necessarily complex and therefore there has a very steep learning curve for beginners to climb before they can really master it.

To find out more about Reaktor 5, hear audio examples, or to download the free demo software from the Native Instruments website, click here.


To hear music and emulations of real world sounds that were created using modular synthesis, or to download Clavia Nord Modular G2 patches, click here.



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